SF-RAG: Structure-Fidelity Retrieval-Augmented Generation for Academic Question Answering

TL;DR

SF-RAG introduces a hierarchical, structure-aware retrieval framework for academic question answering, significantly reducing fragmentation and improving evidence accuracy by leveraging native paper structures.

Contribution

The paper proposes SF-RAG, a novel retrieval method that maintains the native hierarchical structure of papers, enhancing retrieval coherence and evidence allocation in academic QA.

Findings

Reduces retrieval fragmentation significantly.

Improves evidence allocation accuracy.

Enhances answer quality in QA benchmarks.

Abstract

Efficient question-answering (QA) over extensive scientific literature is essential for evidence-based engineering decision-making. Retrieval-augmented generation (RAG) is increasingly applied to question-answering over long academic papers, where accurate evidence allocation under a fixed token budget is critical. However, existing approaches flatten papers into unstructured chunks, destroying the native hierarchical structure and forcing retrieval to operate in a disordered space. This produces fragmented contexts, misallocates tokens to non-evidential regions, and increases the reasoning burden for downstream language models.To address these issues, we propose SF-RAG, an RAG framework that treats the native hierarchical structure of academic papers as a low-entropy retrieval prior.SF-RAG first inherits the native hierarchy to construct a structure-fidelity index, which prevents entropy increase at the source.It then designs a path-guided retrieval mechanism that aligns query semantics to relevant sections and selects high relevance root-to-leaf paths under a fixed token budget, yielding compact, coherent, and low-entropy retrieval contexts.In contrast to existing RAG approaches, SF-RAG avoids entropy increase caused by destructive preprocessing and provides a native low-entropy structural basis for subsequent retrieval. We further introduce entropy-based structural diagnostics to quantify retrieval fragmentation and evidence allocation accuracy.Evaluations across three QA benchmarks show that SF-RAG significantly reduces retrieval fragmentation and improves evidence allocation. These structural benefits drive superior answer quality, establishing a scalable foundation for intelligent engineering document systems and future applications in technical specifications.